The present disclosure generally relates to a stage tool for cementing a wellbore, and in particular systems and methods for sealing stage tool leaks.
The stage tools find its application in conventional and non-conventional wells to enable cementing long columns in two or several stages. Generally, while using cementing tools involving two stages, the tool is placed in the casing string so that the hydrostatic pressure of the cement column does not break down the formation. After the completion of first stage cementation and when the cement has gained enough strength to support hydrostatic pressure, the stage tool is opened and the cement job is performed on the upper half of the well. Many natural terrains require the aforementioned stage tool for successful cementing.
A challenge with conventional stage tools for wellbore cementing is that the sleeves that isolate the inner casing from the annulus, once closed, may leak. This may lead to leakage of wellbore fluids and hydrocarbons to the inside of the casing, requiring remediation and increasing the cost.
A conventional method to prevent leaking involves a cement squeeze. However, the method of cement squeezing does not have a high success rate due to the high pressure exerted at the wellbores on the set cement. Another conventional method of leak protection involves a casing patch. A casing patch requires a rig which may be expensive. Yet another conventional method of sealing uses a stub liner, which increases the complexity of the tool and also increases the cost of production. Therefore, there exists the need for improved devices, methods, and systems for sealing stage tool leaks.